 ;; You must not remove this notice, or any other, from this software.
 
 (ns conexp.contrib.algorithms.downing-gallier
-  (:use [conexp.base :only (not-yet-implemented, def-)]
+  (:use [conexp.base :only (not-yet-implemented, difference)]
         [conexp.fca.implications :only (premise conclusion)]))
 
 ;;; Implementation

    #{1 2 3 4 5 6 7 8} [[#{1} #{4}] [#{2} #{3}] [#{4} #{5 6 7}] [#{6 7} #{8}] [#{9 10 11} #{8}]] #{1 2 3 4 5 6 7 8}))

(test/deftest test-clop-by-implications
  (let [clop (clop-by-implications #{(make-implication #{1} #{2}),
                                     (make-implication #{3} #{4}),
                                     (make-implication #{} #{1})})]
    ;;
    (test/is (= #{1 2} (clop #{1}) (clop #{2}) (clop #{})))
    (test/is (= #{1 2 3 4} (clop #{3})))

(test/deftest test-close-under-implications
  (test/are [start impls result]
    (= result
       (close-under-implications (map (partial apply conexp/make-implication)
                                      impls)
                                 start))
    ;;
